Allodaposuchus palustris sp. nov. from the upper cretaceous of Fumanya (South-Eastern Pyrenees, Iberian Peninsula): systematics, palaeoecology and palaeobiogeography of the enigmatic allodaposuchian crocodylians.

Alejandro Blanco,Bernat Vila,Josep Marmi,Eduardo Puértolas-Pascual,Albert G Sellés,Peter Dodson

doi:10.1371/journal.pone.0115837

Abstract

The controversial European genus Allodaposuchus is currently composed of two species (A. precedens, A. subjuniperus) and it has been traditionally considered a basal eusuchian clade of crocodylomorphs. In the present work, the new species A. palustris is erected on the base of cranial and postcranial remains from the lower Maastrichtian of the southern Pyrenees. Phylogenetic analyses here including both cranial and postcranial data support the hypothesis that Allodaposuchus is included within Crocodylia. The studied specimen suggests little change in postcranial skeleton along the evolutionary history of crocodylians, except for some bone elements such as the axis, the first caudal vertebra and the ilium. The specimen was found in an organic mudstone corresponding to a coastal wetland environment. Thus, A. palustris from Fumanya is the first Allodaposuchus reported in lacustrine-palustrine settings that expand the ecological range for this genus. The S-DIVA palaeobiogeographic reconstruction of ancestral area suggests that early members of Crocodylia rapidly widespread for the Northern Hemisphere landmasses no later than the Campanian, leading the apparition of endemic groups. In that way “Allodaposuchia” represents an endemic European clade probably originated in the Ibero-Armorican domain in the late Campanian and dispersed by the Southern European archipelago prior to the early Maastrichtian.

Highlights

The clade of eusuchian crocodylomorphs is composed of several stem taxa and the crown Crocodylia containing the three major extant lineages: Crocodyloidea, Alligatoroidea and Gavialoidea [1,2,3,4]
The most parsimonious hypothesis obtained in our analyses suggests that the clade (Allodaposuchus + Arenysuchus) belongs to Crocodylia (Fig. 8)
According to Brochu [20], the inclusion of the clade (Allodaposuchus + Arenysuchus) within Crocodylia would be supported by the following synapomorphies: 1) anterior dentary teeth project anterodorsally, 2) retroarticular process projects posterodorsally, 3) exoccipital lacks boss on paraoccipital process, and 4) hypapophyseal keels are present on the eleventh vertebrae behind the atlas

Summary

Introduction

The clade of eusuchian crocodylomorphs is composed of several stem taxa and the crown Crocodylia containing the three major extant lineages: Crocodyloidea, Alligatoroidea and Gavialoidea [1,2,3,4]. During the Late Cretaceous, eusuchians were widespread in Europe [6]. There were members of the sister taxa of Crocodylia, such as Hylaeochampsidae (e.g. the English Hylaeochampsa vectiana Owen, the Italians Pietraroiasuchus ormezzanoi Buscalioni et al and Acynodon adriaticus Delfino et al, the Iberian Acynodon iberoccitanus Buscalioni et al and the Hungarian Iharkutosuchus makadii Osi et al.) and the genus Allodaposuchus (according to Puertolas-Pascual et al [5]). Several species of basal gavialoids attributed to the genus Thoracosaurus have been described from the Late Cretaceous of France, Netherlands and Crimea [6]

Objectives

Methods

Discussion

Conclusion